/* ===========================================================
 * Global theme — edit here to retune fonts/colors site-wide.
 * =========================================================== */
:root {
  /* Typography */
  --font-body: "Inter", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-display: "Inter", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", Menlo, Consolas, monospace;

  --font-size-base: 17px;
  --line-height-base: 1.65;
  --reading-width: 720px;
  --side-margin: 220px; /* room for figure captions */

  /* Palette — clean white background, paper-aligned accents */
  --color-bg: #ffffff;
  --color-surface: #ffffff;
  --color-text: #111111;
  --color-text-muted: #6b6b6b;
  --color-rule: #e6e6e6;

  --color-dirichlet: #b8362a;   /* warm */
  --color-neumann:   #2a5fb8;   /* cool */
  --color-interface: #e88c30;   /* tile interfaces */
  --color-tile-grid: #888888;
  --color-accent:    #2a5fb8;
  --color-walk:      #1a1a1a;

  /* Heatmap stops (warm/cool diverging, RdBu-ish reversed) */
  --hm-low:  #2a5fb8;
  --hm-mid:  #f7f7f4;
  --hm-high: #b8362a;

  /* UI */
  --radius: 4px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04), 0 0 0 1px rgba(0,0,0,0.04);
}